We stayed up late night and we were so tired -> If...

$\text{We stayed up late night and we were so tired}$

$\longrightarrow$ $\text{If we didn't stay up late at night, we wouldn't be so tired.}$

$\longrightarrow$ $\text{Câu điều kiện loại 2}$

$\longrightarrow$ $If + S + V2/ Ved, S + Would/ Could/ Should… + V$

$\longrightarrow$ $If + QKĐ,  HTĐ/HTTD$

$\longrightarrow$ $\text{If this thing happened that thing would happen.}$

$\longrightarrow$ $\text{To be: were/weren't}$

Câu trả lời là:

We stayed up late night and we were so tired

-> If we hadn't stayed up late, we wouldn't have tired

=> Câu cũ khẳng định sang if thì phải chuyển thành phủ định

-> stayed , were là động từ ở thì quá khứ đơn nên sự việc đã xảy ra

-> Mong muốn 1 điều trái với quá khứ dùng điều kiện loại 3

-> Cấu trúc: If + S + had + V p.p , S + would(not)+have + V p.p